Biomedical subjects

J C Baumgartner

Publications and source records attributed to J C Baumgartner.

At least 37 records · Page 2Linked to original sources

PubMed1998

Perforation repair comparing mineral trioxide aggregate and amalgam using an anaerobic bacterial leakage model.

The purpose of this study was to evaluate the ability of mineral trioxide aggregate (MTA) and amalgam to seal furcal perforations in extracted human molars using an anaerobic bacterial leakage model. Furcal perforations were made in 39 maxillary and mandibular human molars with a high-speed bur. These were randomly divided into two experimental groups of 18, with the remaining three teeth used as positive controls. Experimental group 1 was repaired with MTA and group 2 with amalgam. Three additional teeth without perforations served as negative controls. A dual chamber anaerobic bacterial leakage model was assembled. Brain heart infusion broth with yeast extract, hemin, menadione, and the chromogenic indicator bromcresol purple was used as the culture broth for Fusobacterium nucleatum. Eight of 18 amalgam samples leaked, whereas none of the 18 MTA samples leaked. MTA was significantly better than amalgam in preventing leakage of F. nucleatum past furcal perforation repairs.

Aluminum Compounds↗

PubMed1997

Occurrence of Prevotella nigrescens and Prevotella intermedia in infections of endodontic origin.

The occurrence of Prevotella intermedia and Prevotella nigrescens in endodontic infections was studied using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of whole cell protein to distinguish between the species. Previous studies have shown an association between black-pigmented bacteria (BPB) and endodontic infections and that Prevotella intermedia (previously known as Bacteroides intermedius) was the most commonly isolated BPB. Recently, however, strains identified as P. intermedia were shown to in fact be composed of two separate species, P. intermedia and P. nigrescens. Fifty-six strains of BPB isolated from endodontic infections and previously identified as P. intermedia were used in this study. Following SDS-PAGE, P. nigrescens showed a unique 18.6 kDa band that was used to differentiate P. nigrescens from P. intermedia. Of the 56 strains of BPB, 41 (73.2%) were identified as P. nigrescens and 15 (26.8%) as P. intermedia. This study confirms that P. nigrescens, and not P. intermedia, is the BPB most often isolated from infections of endodontic origin.

Amino Acid Sequence↗

PubMed1997

Comparison of ultrasonic and high-speed-bur root-end preparations using bilaterally matched teeth.

The purpose of this study was to compare ultrasonic and high-speed-bur root-end preparations. Seventy-six roots from 29 bilaterally matched pairs of human teeth in cadavers were used in this study. In group 1 ultrasonic preparations were made in 38 roots and filled with amalgam. In group 2 high-speed bur preparations were made in 38 roots and filled with amalgam. The size of the bony crypt was measured and the teeth were extracted and radiographed mesial-distally and buccal-lingually. None of the root-end preparations resulted in root perforation. The mean mesial-distal minimum depth of ultrasonic and high-speed bur preparations were 2.11 mm and 1.39 mm, respectively. The mean buccal-lingual minimum depth of preparation was 2.51 mm for the ultrasonic and 2.05 mm for the high-speed bur preparations. The depth of the ultrasonic preparations was significantly greater for both measurements. A significantly greater bevel angle was associated with the bur preparations, 35.1 degrees versus 16.0 degrees for the ultrasonic preparations. The incidence of ultrasonic root-end preparations deviating from the uninstrumented canal spaces was found to be 2.6%. All bur root-end preparations were at an acute angle to the long axis of the root. The bony crypt size for bur preparations was significantly greater than that for ultrasonic preparations.

Cadaver↗

PubMed1997

A comparison of canal centering ability of four instrumentation techniques.

The purpose of this study was to compare three engine driven (nickel-titanium) NiTi instrument systems with hand files for their effect on canal transportation. Mesial roots of mature lower first molars with separate canals were paired on the basis of curvature and morphology. Canal lengths were standardized to 11 mm from orifice to apical foramen. Profile, Lightspeed, McXIM, and Flex-R hand filing techniques respectively were randomly assigned to one of the four canals of each tooth pair. The roots were mounted and sectioned at 1 mm, 3 mm, and 5 mm from working length using a modified Bramante technique. All sections were video imaged preoperatively after instrumentation to size #30 and after final instrumentation to size #40. The images were computer analyzed for changes in canal area and centering at each stage of instrumentation. Preparation time was also recorded. Data were analyzed using ANOVA. The NiTi systems remained better centered in the canal than stainless steel hand files. There were no significant differences among the NiTi systems at any level. The difference between hand filing and the NiTi techniques was more pronounced at size #40 than at size #30. The NiTi systems were all significantly faster than hand filing. No significant differences in preparation were found between the NiTi systems when canals were instrumented to the size nearest #40.

Analysis of Variance↗

PubMed1997

Comparison of dentinal crack incidence and of post removal time resulting from post removal by ultrasonic or mechanical force.

The purpose of this study was to compare the frequency of canal and intradentin cracks after intraradicular post removal using ultrasonic instrumentation or the Gonan post removal system. Sixty cadaver teeth were divided into 4 groups of 15 teeth each: group 1, ultrasonic removal; group 2, Gonan post removal system; group 3, cemented posts not removed; and group 4, no posts. Groups 1 and 2 were contralateral matched pairs. Para Posts were placed in groups 1, 2, and 3 to 7 mm apical to the cementoenamel junction and luted with ZnPO4 cement. The time required for post removal in groups 1 and 2 was recorded. The teeth were extracted, sectioned, and examined. Canal and intradentin cracks were mapped, and their frequency was recorded at each level. There were statistically more cracks present in the ultrasonic group than the no post group. There were no other differences that reached statistical significance. It took significantly longer for post removal using the ultrasonic tip versus the Gonan system.

Cadaver↗

PubMed1997

Evaluation for cracks associated with ultrasonic root-end preparation of gutta-percha filled canals.

Many clinicians use ultrasonics for root-end preparations. The purpose of this study was to evaluate resected root-end surfaces of bilaterally matched human teeth for cracks before and after ultrasonic root-end preparation. Twenty matched pairs of extracted single rooted teeth were divided into two experimental groups. In group 1, root-end resection was performed on uninstrumented teeth. In group 2, root-end resection was performed after the canals were instrumented and filled with gutta-percha. All teeth in both groups received root-end preparations using ultrasonic instrumentation at low power. Two examiners evaluated the root-ends after root-end resection and again after root-end preparation using zoom magnification of 20x to 63x. The number, types, and location of cracks were mapped. There were no significant differences when gutta-percha filled roots were compared to uninstrumented roots with regard to the number or type of cracks after root-end resection or root-end preparation. In addition, there were no significant differences in the number or type of cracks following root resection and ultrasonic root-end preparation when compared to teeth with root resection alone.

Analysis of Variance↗

PubMed1997

Demineralization of resected root-ends with methylene blue dye.

OBJECTIVES: This study evaluated the ability of methylene blue solutions of different concentration, pH, and time exposure to remove the smear layer from resected root-ends. STUDY DESIGN: Resected root-ends were treated with either 2% methylene blue dye for intervals of 5 to 11 minutes or 1% methylene blue for 7 to 9 minutes and examined with a scanning electron microscope for smear layer removal. Two minute applications of saline solution and 50% citric acid served as controls. RESULTS: All methylene blue solutions were found to be ineffective in removing the smear layer at all time intervals tested. An experimental solution of 1% methylene blue in 50% citric acid was found to predictably remove the smear layer during a 2 minute application and retained all the favorable staining characteristics of the dye. Fifty percent citric acid solutions applied for 3 minutes appeared to overdemineralize the root-end and gave poorer results than 2 minute applications. CONCLUSIONS: Smear layer removal was pH dependent. Methylene blue solutions are clinically unsuitable for smear layer removal.

Adult↗

PubMed1996

Evaluation of cracks associated with ultrasonic root-end preparation.

The purpose of this study was to evaluate the integrity of resected root-end surfaces of extracted human teeth after using ultrasonic tips at low or high frequencies for root-end preparation. Thirty bilaterally matched pairs of single-rooted human teeth had root-end resections using a low-speed diamond saw and were examined for root-end cracks. The matched pairs of teeth were then divided into two experimental groups, with one member of each pair being placed in each group. In group 1, root-end preparations were made with an ultrasonic tip on the lowest frequency setting. The preparations in group 2 were done on the highest power setting. Two investigators again examined the resected root-ends using a stereomicroscope at x20 to x63 and recorded the numbers, types, and location of the cracks. Three types of cracks were observed: canal cracks, intradentin cracks, and cemental cracks. There were significantly more root-ends with cracks after ultrasonic root-end preparation than after root-end resection only. In root-ends that had any cracks, significantly more canal cracks per root occurred when the ultrasonic tip was used on the high-frequency setting for root-end preparation than when the ultrasonic tip was used on the low power setting.

Apicoectomy↗

PubMed1995

Effects of a carbon dioxide laser on human root dentin.

The effects of the Luxar LX-20 CO2 dental laser on resected apical root dentin were examined using stereomicroscopy and scanning electron microscopy. The surfaces of 2-mm-thick sections of dentin from freshly extracted human teeth were exposed to CO2 laser radiation. Fluences used ranged from 2.1 to 625.0 J/cm2. The effects of the laser energy on the dentin ranged from no visible effects, to charring, cracking, cratering, and glazing. The most dramatic effect was cracking. Cracking was evident on all specimens having any visible modification of the dentin. A prototype-curved laser tip was used and compared with a standard straight tip. The curved tip did not deliver laser energy to the dentin as efficiently as a straight tip. CO2 laser radiation did not consistently obliterate dentin tubules.

Dentin↗

PubMed1995

Evaluation of root thickness in curved canals after flaring.

Root thickness in the mesial canals of lower first and second molars was compared before and after flaring by using a muffle system. Gates Glidden burs or M-Series Canal Openers were used with either a straight up-and-down motion or with an anticurvature motion. It was found that Gates Glidden burs used straight up and down removed statistically more dentin at the level of the furcation than Canal Openers used straight up and down or in an anticurvature fashion. At a level 2 mm apical to the furcation, Gates Glidden burs used in an anticurvature fashion removed statistically more dentin than any other method tested.

Analysis of Variance↗

PubMed1995

Practical application of infection control in endodontics.

The transmission of infections in an endodontic practice is a significant concern for both patients and dental health care providers. This article offers a review and practical application of infection control methods in the practice of endodontics.

Disinfectants↗

PubMed1994

Adult pulpal diagnosis. I. Evaluation of the positive and negative responses to cold and electrical pulp tests.

This study investigated the positive and negative responses of 1488 teeth in 60 patients to two electric pulp testers and a cold thermal pulp test. Three subgroups of known pulpless or pulpally diseased teeth (teeth receiving root canal therapy, teeth with root canal fillings, or teeth with confirmed associated apical radiolucencies) were identified and their responses evaluated separately. Testing was performed on two tooth surfaces, the facio-occlusal and faciocervical, and on all restorations. The gingival tissue of each patient also was tested using both electrical tests. The primary findings were: (a) teeth not responding to cold and either not responding or responding at readings greater than the tissue response to electrical had a high probability of being in the known pulpless or pulpally diseased subgroups; (b) the only false positive responses to cold in the three subgroups were in multirooted teeth with probable vital tissue remaining in at least one canal; and (c) in the three subgroups, if the false positive responses to electrical that responded at levels higher than the patient's tissue response were considered to be negative responses, the difference in false positives between cold and electrical became not statistically significant (p = 0.07).

Adult↗

PubMed1993

Development of chronic mandibular osteomyelitis in a miniswine model.

Previous attempts to develop a reproducible model of chronic mandibular osteomyelitis have met with limited success. In this study, osteomyelitis was produced in the mandibles of eight adult Yucatan miniswine by the intramedullary application of sodium morrhuate, Staphylococcus aureus, and either polymethylmethacrylate bone cement or bone wax. At 8 weeks' postinfection, the mandibles were surgically debrided and specimens were obtained for culture. Although all of the animals developed clinical evidence of osteomyelitis that was supported by positive cultures, the original organism (S aureus) was recovered only from those animals where bone wax had been used to seal the cortical defects. This animal model may be useful for evaluating newer treatment modalities for chronic osteomyelitis.

Animals↗

PubMed1992

Histomorphometric comparison of canals prepared by four techniques.

Numerous methods of root canal preparation have been recommended and used by clinicians. This study used histomorphometrics to determine the area of root canal preparations using four currently popular techniques. Clinicians that were highly skilled in each technique prepared curved canals in acrylic blocks. Each clinician described this technique and discussed the technique with regard to the use of acrylic blocks as compared with dentin. Analysis of the areas of the root canals after preparation revealed a significant difference among the groups. The mean areas after treatment were step-back technique, 17.33 mm2; Cavi-Endo technique, 15.87 mm2; Canal Master technique, 13.56 mm2; and balanced force technique, 17.31 mm2. Photographs of the blocks used in the study were included for inspection by the reader.

Dental Cavity Preparation↗

PubMed1992

Efficacy of several concentrations of sodium hypochlorite for root canal irrigation.

Sodium hypochlorite (NaOCl) has been recommended for irrigation during root canal preparation. This investigation used scanning electron microscopy to examine instrumented and uninstrumented surfaces in the middle third of root canals following the use of several concentrations of NaOCl (5.25%, 2.5%, 1.0%, and 0.5%). NaOCl was delivered with either an endodontic irrigation needle or an ultrasonic device. All of the concentrations of NaOCl with either delivery system were very effective in flushing out loose debris from the root canals. A smear layer with some exposed dentinal tubules was seen on all instrumented surfaces regardless of concentration of NaOCl or irrigation device. NaOCl in concentrations of 5.25%, 2.5%, and 1% completely removed pulpal remnants and predentin from the uninstrumented surfaces. Although 0.5% NaOCl removed the majority of pulpal remnants and predentin from the uninstrumented surfaces, it left some fibrils on the surface.

Bicuspid↗

PubMed1992

Experimentally induced infection by oral anaerobic microorganisms in a mouse model.

A mouse model was developed to study the abscessogenic potential of pure and mixed cultures of oral anaerobes associated with infections of endodontic origin. Maximum subcutaneous lesions were seen on their backs between 3 and 14 d after inoculation. Strains of Fusobacterium nucleatum, Peptostreptococcus anaerobius, and Veillonella parvula were pathogenic in pure culture. A mixed culture of F. nucleatum with either Porphyromonas gingivalis or Prevotella intermedia was significantly more pathogenic than F. nucleatum in pure culture. Histopathological examination of tissue sections from control mice injected with India ink in the medium demonstrated a pathway of particulate migration from the backs of the mice to their abdomen.

Abdomen↗

PubMed1992

Serum IgG reactive with oral anaerobic microorganisms associated with infections of endodontic origin.

Numerous species of bacteria have been implicated with infections of endodontic origin. The purpose of this study was to compare the levels of serum IgG antibodies reactive with a panel of 10 oral anaerobic microorganisms implicated in infections of endodontic origin. Serum samples were collected from 4 patient groups that included healthy patients without endodontic or periodontal disease, patients with chronic adult periodontal disease, patients with endodontic disease and patients with combined endodontic-periodontal disease. When Prevotella intermedia was allowed to react with sera from the 4 patient groups, significant pairwise differences were shown between the healthy group and each of the other 3 groups. In addition, there was a significant difference between the periodontal disease group and the combined endodontic-periodontal disease group. When Porphyromonas gingivalis was allowed to react with sera from the 4 patient groups, significant pairwise differences were shown between the healthy group and the periodontal disease group, the healthy group and the combined endodontic-periodontal disease group, the endodontic disease group and the periodontal disease group and the endodontic disease group and the combined endodontic-periodontal disease group. The results of this investigation support other studies that associate P. intermedia with both endodontic disease and chronic adult periodontal disease. The results also support studies that implicate P. gingivalis as a periodontopathogen.

Actinomyces↗

PubMed1991

Detection of immunoglobulins from explant cultures of periapical lesions.

The presence of immunoreactive cells in periapical inflammatory lesions suggests that immune responses participate in the disease process. The purpose of this study was to determine the presence and concentration of immunoglobulins in the supernatant fluids of explant cultures of periapical lesions. Ninety periapical lesions that had been contiguous with the apex of a root were removed and maintained in explant cultures for 96 h. Tissue culture medium was replenished at 24, 48, 72, and 96 h. Double diffusion in agarose assays demonstrated the presence of IgG in 100% of the 24-h supernatant fluids and IgA in 65% of the 24-h supernatant fluids. However, IgM was not detected. Radial immunodiffusion assays were used to detect and quantitate IgG, IgA, and IgM in samples of 24-h supernatant fluids from 90 explant cultures. IgG was the predominant immunoglobulin followed by IgA. A radioimmunosorbent test was used to detect and quantitate IgE in samples of 24-h supernatant fluids from 90 explant cultures. Forty of the 90 supernatant fluids contained measurable IgE. All detected immunoglobulins decreased in concentration in daily supernatant fluids with time (24, 48, 72, and 96 h) in the culture.

Adolescent↗